1. Field of the Invention
The present invention relates to an auto light intensity adjustment system, and in particular relates to an auto light intensity adjustment system utilized on an aiming device.
2. Description of the Related Art
FIGS. 1 and 2 show a conventional aiming device disposed on a gun. The aiming device comprises an outer tube 1, an objective lens unit 2 disposed on a front end of the outer tube 1, an eyepiece unit 3 disposed on a rear end of the outer tube 1, a multiplier unit 4, two impact point compensation units 5 for compensating for deviation and an aiming unit 6. The aiming unit 6 comprises an aiming sheet 61 and a light source 62. The aiming sheet 61 is disposed on a rear end of an inner tube 401. The aiming sheet 61 comprises a hairline portion 611 for aiming. The light source 62 comprises a fixing base 621 disposed on the rear end of the outer tube 1, a variable resistor 622 disposed in the fixing base 621, a circuit board 623 disposed in the fixing base 621, a battery bearer 624 disposed on the fixing base 621, a battery 625 disposed in the battery bearer 624, an operation ring 626 disposed on the battery bearer 624, a seal cover 627 sealing the battery bearer 624, a refractive ring 628 disposed in the outer tube 1 behind the aiming sheet 61, and an LED element 629 disposed on the refractive ring 628.
When a user aims and shoots the gun in a bright environment at a target, the user rotates the operation ring 626 to increase light intensity of an LED element. The light of the LED element 629 is refracted by the refractive ring 628 to the hairline portion 611 of the aiming sheet, and the hairline portion 611 reflects the light to form a illuminated aiming mark. Therefore, the user is allowed to aim with a brighter hairline portion 611 under a bright environment. However, when the target moves from a darker to a brighter environment, the user must manually increase brightness of the aiming mark to show the aiming mark clearly on an aiming window. In this situation, the user must stop aiming at the target and view and rotate the operation ring 626 to adjust the intensity of the light. Thus, during the time of the adjustment, the target may disappear. As such, shortcomings exist with the light intensity adjustment method of conventional aiming devices.